164 MR. ST. GEORGE MIVART ON MICRORHYNCHTJS. [Mar. 13, 



the inner surface of the ulnar ridge of trochlea (again like Indris and 

 unlike Lemur) is entirely behind the internal condyle. 



The capitellum has a concavity outside the rounded head. The 

 radial ridge of the trochlea is remarkably prominent. 



Radius. — This is much longer in proportion than is the humerus. 

 Taking the latter at 100, the radius is 114 - 7 long, nearly equalling 

 the proportion of Indris (viz. 1 1 6 • 5 ), and greatly exceeding that of 

 Lemur (91 • 6), or of any of the Lemuridce, Loris approaching nearest, 

 however, and being 1 10*2. 



It is slightly more slender than in Lemur, though not so much 

 so as in Indris ; but it rather agrees with the latter, and differs 

 from Lemur in the rounded shape of the bone towards the ulna, and, 

 indeed, of its radial side also. It agrees with Indris also, and differs 

 from Lemur, in that the inferior (distal) border of the anterior (flexor) 

 surface is not prominent and produced ; on the other hand, there is 

 a distinct prominence (from almost the distal extremity of the radial 

 margi:;), as if for the supinator longus ; but it may be for the pronator 

 quadratus. As in Indris the anterior surface is rounded, and not 

 grooved from the flexor longus pollicis as in Lemur. 



Vina. — This bone, although not so distant from the radius as in 

 Indris, is nevertheless more so than in Lemur ; hence perhaps the 

 less grooved condition of the bones, the interosseous membrane thus 

 affording a wider space for muscular attachment. 



The ulna has a similar excess over the humerus to the radius, 

 namely as 127'G to 100. In Indris it is 132, but in Lemur only 

 U35. 



As in Indris, it is a much more slender bone than in Lemur ; indeed 

 it is very slender. 



It is remarkable for the very small size of the olecranon, differing 

 from Lemur in this even more than Indris does. 



As in Indris, the only fossa for the origin of the flexor profundus 

 digitorum is situated beneath the sigmoid cavity; nor is there any 

 groove extending down the shaft of the bone for the extensor pollicis 

 as in Lemur — thus again agreeing with Indris, as also in the fact 

 that there is scarcely any trace of a ridge for the pronator quadratus, 

 which, on the contrary, attains its maximum in Lemur. 



The carpus presents a most remarkable character, noticed by De 

 Blainville, inasmuch as it agrees with that of Indris, and differs from 

 that of all the other Primates, except Man and Troglodytes, in the fact 

 of possessing no os intermedium, and having only eight carpal bones. 

 It agrees with that of Indris, except that the pisiforme is smaller. 



In my specimen the third metacarpal is slightly the longest, thus 

 differing from DeBlainville's* specimen. It is to the radius (taking 

 the latter at 100) as 31 - 8, which is almost its proportion in Indris, 

 where it is Sl'l. In Lemur it is only 26 , 4. 



The metacarpal of the index is not so curved as in Indris ; but it 

 preponderates more over that of the pollex, which is here very short, 

 the proportion of the metacarpal of the index to that of the pollex 

 being as 183-3 to 100, while in Indris it is only 151*8 to 100. The 



* Loc. cit. p. 23. 



